When an electrical charge travels in lightning to Earth, what is the width of the column of air?
According to C. D. Ahrens in Meteorology Today, it is the return stroke, the upward surge of positive charge meeting the downward flow of electrons, that is more visible and the one generally identified as a lightning strike. It may be several centimeters in diameter. Do you have suggestions how one may assist students with the concept of the surface area-to-volume ratio of a cell? We will address the plant cell, often a rectangular shape. Create an imaginary cell by stacking sugar cubes. Have the cell “grow” by adding cubes: w x l x h = volume in cubic units. Record the volume and surface area each time you add a cube. Graph the surface area/volume ratios to sugar cube volume, with volume on the x axis and ratios on the y axis (Cognition Applied to Science Teaching, NSF/CAST Institute, 1990). How do piezoelectric crystals work? These crystals become strained when subjected to electric fields; the deformation is directly proportional to the field and it reverses in sign as the sign of
